A conventional memory card (child machine or ancillary machine) that is used inserted into the main unit (parent machine or host machine) of an information device such as a video game machine, is constructed so as to have an interface for connecting with the parent device and a nonvolatile memory element for storing data.
FIG. 1A shows a composition of the main part of a memory card as one example of a memory device of a conventional portable electronic device. The conventional memory card 10 has a control unit 11 for controlling its operation, a connector 12 for connecting to a terminal provided in a slot of the parent machine, and a nonvolatile memory 16 for storing data. Connector 12 and nonvolatile memory 16 are connected to control unit 11.
Control unit 11 is constructed using, for example, a microprocessor (labeled as such in the diagram). As nonvolatile memory 16, an EEPROM or other flash memory may be used. For the connection interface with the main unit, a microprocessor is sometimes used as a control means for interpreting protocols.
FIG. 1B shows the control elements in control unit 11 of conventional memory card 10.
The conventional memory card 10 has had only a main unit connection interface 13 for connecting to the main unit, and a memory interface 14 for inputting and outputting data to and from the nonvolatile memory 16.
Also, a conventional video game device has the function of storing game data, etc. in an auxiliary memory device. The memory card 10 is used as an auxiliary memory device of such a video game device.
FIG. 2 shows an example of a conventional video game device 1 that uses a memory card 10 as an auxiliary memory device. Main unit 2 of the video game device 1 is housed in a roughly square-shaped housing and consists of a disk mounting unit 3 in the middle of which is mounted an optical disk that is a recording medium on which are recorded application programs for video games, a reset switch 4 for arbitrarily resetting the game, a power switch 5, a disk operation switch 6 for operating the mounting of said optical disk, and, for example, two slots 7A and 7B.
Memory card 10, which is used as an auxiliary memory device, is inserted into these slots 7A and 7B, and for example the results of games executed on video game device 1 are sent from a control device (CPU) 19 and are written into nonvolatile memory 16. The construction is such that multiple operation devices (controllers, not shown) can be connected to slots 7A and 7B, allowing multiple users to play a competitive game simultaneously.